(1) Field of the Invention
This invention relates to a semiconductor memory, and more particularly to a nonvolatile semiconductor memory having a plurality of banks.
(2) Description of the Related Art
Flash memories are nonvolatile semiconductor memories and a copy back function has recently been added to some of these flash memories. This copy back function is for transferring data stored in a page to another page without reading out it to the outside.
In recent years the capacity of nonvolatile memories has become large. To store a large amount of data, some semiconductor memories have adopted a method for storing data in a plurality of banks by dividing it.
With such semiconductor memories having a plurality of banks, each bank includes a page buffer. Therefore, transferring data in the same bank can be achieved by storing the data read out in a page buffer and writing the data to the appropriate address.
However, transferring data between banks will need a data transfer between page buffers. Semiconductor memories having such transfer mode are not provided. Therefore, to transfer data between banks, the data is once read out to the outside and then is written again. This process is time-consuming.
The present invention was made under the background circumstances as described above. An object of the present invention is to provide a method for enabling copy back not only in the same bank but also between banks in a nonvolatile semiconductor memory having a plurality of banks.
In order to achieve the above object, a nonvolatile semiconductor memory having a plurality of banks is provided. This semiconductor memory comprises an input circuit for accepting input of a copy back command which requests a data transfer in the memory, a judgment circuit for judging at the time of the copy back command being input from the input circuit whether a source and a destination are in the same bank, a first transfer circuit for transferring, in the case of the judgment circuit judging that the source and the destination are in the same bank, data in the same bank, and a second transfer circuit for transferring, in the case of the judgment circuit judging that the source and the destination are in different banks, data between the two different banks.
The above and other objects, features and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate preferred embodiments of the present invention by way of example.